/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.solr.analysis;

import org.apache.solr.common.ResourceLoader;
import org.apache.solr.util.plugin.ResourceLoaderAware;
import org.apache.lucene.analysis.StopFilter;
import org.apache.lucene.analysis.StopAnalyzer;
import org.apache.lucene.analysis.TokenStream;
import org.apache.lucene.analysis.CharArraySet;

import java.util.Map;
import java.util.Set;
import java.io.IOException;

/**
 * Factory for {@link StopFilter}.
 * 
 * <pre class="prettyprint" >
 * &lt;fieldType name="text_stop" class="solr.TextField" positionIncrementGap="100" autoGeneratePhraseQueries="true"&gt;
 *   &lt;analyzer&gt;
 *     &lt;tokenizer class="solr.WhitespaceTokenizerFactory"/&gt;
 *     &lt;filter class="solr.StopFilterFactory" ignoreCase="true"
 *             words="stopwords.txt" enablePositionIncrements="true"/&gt;
 *   &lt;/analyzer&gt;
 * &lt;/fieldType&gt;
 * </pre>
 * 
 * @version $Id: StopFilterFactory.java 1067552 2011-02-05 23:52:42Z koji $
 */
public class StopFilterFactory extends BaseTokenFilterFactory implements
		ResourceLoaderAware {

	@Override
	public void init(Map<String, String> args) {
		super.init(args);
		assureMatchVersion();
	}

	public void inform(ResourceLoader loader) {
		String stopWordFiles = args.get("words");
		ignoreCase = getBoolean("ignoreCase", false);
		enablePositionIncrements = getBoolean("enablePositionIncrements", false);

		if (stopWordFiles != null) {
			try {
				stopWords = getWordSet(loader, stopWordFiles, ignoreCase);
			} catch (IOException e) {
				throw new RuntimeException(e);
			}
		} else {
			stopWords = new CharArraySet(luceneMatchVersion,
					StopAnalyzer.ENGLISH_STOP_WORDS_SET, ignoreCase);
		}
	}

	private CharArraySet stopWords;
	private boolean ignoreCase;
	private boolean enablePositionIncrements;

	public boolean isEnablePositionIncrements() {
		return enablePositionIncrements;
	}

	public boolean isIgnoreCase() {
		return ignoreCase;
	}

	public Set<?> getStopWords() {
		return stopWords;
	}

	public StopFilter create(TokenStream input) {
		StopFilter stopFilter = new StopFilter(luceneMatchVersion, input,
				stopWords, ignoreCase);
		stopFilter.setEnablePositionIncrements(enablePositionIncrements);
		return stopFilter;
	}
}
